/**

*

MDN Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split

The split() method splits a String object into an array of strings by separating the

string into substrings, using a specified separator string to determine where to make each split.

The method has two optional arguments:

- separator: defines the points at which each split should occur.

- limit: integer specifying a limit for the number of splits.

It returns an array of strings split at each point defined by the separator.

Example 1: no arguments passed

"No arguments".split();

must return:

[ "No arguments" ]

Example 2: passing separator and limit

"Oh brave new world that has such people in it.".split(" ", 4);

must return:

[ "Oh", "brave", "new", "world" ]

Example 3: array

"ca,bc,a,bca,bca,bc".split(["a", "b"])

must return:

[ "c", "c,", "c", "c", "c" ]

Example 4: regex

"foobarfoobarfoobar".split(/bar/)

must return:

[ "foo", "foo", "foo", "" ]

Example 5: regex with capturing group

"Hello 1 word. Sentence number 2.".split(/(\d)/)

must return:

[ "Hello ", "1", " word. Sentence number ", "2", "." ]

*/

String.prototype.split = function mySplit(separator, limit) {

const returnValue = [];

let copyThis = '';

// join characters into a string

for (let i = 0; i < this.length; i += 1) {

copyThis += this[i];

}

// check if there is a null separator

if (separator === null || separator === undefined) {

if (limit !== 0) {

returnValue.push(copyThis);

}

} else {

let finalSeparator = separator;

// check if separator is regex

if (

Object.prototype.toString.call(finalSeparator) === '[object RegExp]'

) {

let isDone = false;

let counter = 0;

while (!isDone) {

// checks if theres a limit

if (limit !== null && limit !== undefined) {

if (counter >= limit) {

isDone = true;

break;

}

}

counter += 1;

// executes regex

const regexResult = finalSeparator.exec(copyThis);

// if it has found something, adds prior text to array

// and removes the first occasion of regex

if (regexResult !== null) {

let text = '';

for (let i = 0; i < regexResult.index; i += 1) {

text += copyThis[i];

}

copyThis = copyThis.substr(regexResult.index + regexResult[0].length, copyThis.length);

returnValue.push(text);

// check if it has a capturing group on regex

if (regexResult.length > 1) {

returnValue.push(regexResult[0]);

}

} else {

returnValue.push(copyThis);

isDone = true;

}

}

} else {

// check if separator is array

if (

Object.prototype.toString.call(finalSeparator) === '[object Array]'

) {

// transforms to a string

finalSeparator = '';

for (let i = 0; i < separator.length; i += 1) {

finalSeparator += separator[i];

if (i < separator.length - 1) {

finalSeparator += ',';

}

}

}

// check if separator is empty string

if (finalSeparator !== '') {

let isDone = false;

let counter = 0;

while (!isDone) {

if (limit !== null && limit !== undefined && limit >= 0) {

if (counter >= limit) {

isDone = true;

break;

}

}

counter += 1;

const index = copyThis.indexOf(finalSeparator);

// if it has found the index of separator, add prior text

// and remove the first occasion of separator

if (index !== -1) {

let text = '';

for (let i = 0; i < index; i += 1) {

text += copyThis[i];

}

copyThis = copyThis.substr(index + finalSeparator.length, copyThis.length);

returnValue.push(text);

} else {

returnValue.push(copyThis);

isDone = true;

}

}

} else {

// if it is an empty string, just separate characters from string

// also check if theres a limit defined

const finalLimit = limit !== null && limit !== undefined && limit >= 0

? Math.min(limit, this.length)

: this.length;

for (let i = 0; i < finalLimit; i += 1) {

returnValue.push(copyThis[i]);

}

}

}

}

return returnValue;

};